Switching apparatus



Dec. 15, 1959 Filed March 17, 1958 J. V. FOSTER ETAL SWITCHING APPARATUS 2 Sheets-Sheet 1 ATTORNEY Dec. 15, 1959 J. v. FOSTER ETAL SWITCHING APPARATUS Filed March 1'7, 1958 2 Sheets-Sheet 2 INVENTORS J. VANCE FOSTER PAUL A. HANOLD ATTORNEY United States Patent SWITCHING APPARATUS Jack V. Foster and Paul A. Hanold, Fort Branch, Ind.,

assignors, by mesne assignments, to American Machine & Foundry Company, a corporation of New Jersey This invention relates to electrical switching and particularly to a novel impulse type switching device vincorporating improved means for operating snap action switch mechanisms.

Many types of snap action mechanisms are presently in commercial use and prior art workers have developed numerous means for actuating such mechanisms. When it has been necessary, however, to employ a single power device, and particularly an electromagnetic coil and armature, for operating a plurality of snap acting switch mechanisms, prior art workers have encountered practical problems in attempting to arrive at an entirely satisfactory mechanism for applying the output of the single power device to the several snap acting switch mechanisms.

It is accordingly an object of the invention to provide novel and particularly effective means for transmitting the power output of a single electromagnetic actuator to the operating devices of a plurality of snap acting switch mechanisms.

Another object is to provide, in switching devices of the type referred to, novel actuating mechanism of the impulse type which is more dependably repetitive in its operation than has been the case with mechanisms of this type proposed in the prior art.

A further object is to devise novel motion transfer means for rockinga switch actuating arm in response to pivotal movement of the armature of an electromagnetic power device.

In order that the manner in which these and other objects are accomplished in accordance with the invention can be understood in detail, reference is had to the accompanying drawings, which form a part of this specification, and wherein:

Fig. 1 is a side elevational view of a switching device constructed in accordance with one embodiment of the invention;

Fig. 2 is a plan view of the device of Fig. 1;

Fig. 3 is a front elevational view of the device of Fig. 1, with the electromagnetic power means in de-energized condition;

Fig. 4 is a view identical with Fig. 3 except showing the power means in energized condition, and

Fig. 5 is a detail elevational view of a combination guide and stop means forming part of the device of Fig. 1.

Referring now to the drawings in detail, it will be seen that the embodiment of the invention here illustrated comprises a base plate 1 provided with mounting ears 2 by which the device can be mounted on a surface which may be either horizontal or at an angle to the horizontal. For clarity of description, it will be considered that the device is mounted on a horizontal surface and that the base plate 1 is therefore at the bottom.

of the device.

Secured to base plate 1, in any suitable fashion, are two overlapping frame plates 3 and 4. Frame plate 3 is provided with upright flanges 5, 6 and7, flange 5 being located at what will hereafter be termed, for con- 2,917,598 Patented Dec. 15, 1959 venience, the front of the device and flanges 6 and 7 being disposed each at a difierent side of plate 3. Frame plate 4 is provided with a single uprightflange 8 having, at its tip, two transversely spaced, upwardly projecting extensions 8a. An electromagnetic actuating coil 9 is disposed within the area enclosed by flanges 58, one end of the bobbin on which the coil is wound being seated on the top surface of frame plate 4. The actuating coil 9 can be of any conventional construction, and of course employs the usual magnetic core 10, Fig. 2. The coil can be secured in place, for example, by fastening means extending through plates 1, 3 and 4 and engaged in the core.

The device embodies a pivoted armature 11 of rigid, flat, magnetic material. Armature 11 includes a rectangular body portion 12 and upright end flanges 13 and 14 which extend upwardly from body portion 12 at right angles thereto. Flange 13 is provided with an upwardly opening notch 15, while flange 14 is provided with a circular aperture 16, the center of aperture 16 and the center of the semicircular bottom edge portion of notch 15 being disposed on a line extending above and parallel to body portion 12. Adjacent end flange 13, body portion 12 of the armature is provided with transversely aligned side notches 17.

Adjacent flange 13, body portion 12 of the armature is provided with an opening comprising a narrow, transversely extending, rectangular portion 18 joined by a semicircular portion 19.

Secured to the outer face of flange 8, as by rivets 20, is a bracket 21. At its upper end, bracket 21 has an upright extension 22 terminating in an enlarged head 23 extending transversely with respect to the longitudinal axis of armature 11. At its bottom end, bracket 21 has a lateral flange 24.

An actuating rod 25 is carried by the end flanges of armature 11 and comprises, at its end disposed at the front of the device, a dependent portion 26 and a tip portion 27, the latter extending from portion 26 toward the rear of the device parallel to body portion 12 of the armature. Thus, it will be observed that the actuating rod 25 is generally in the form of a J. The longer arm of actuating rod 25 extends through aperture 16 and notch 15. At end flange 13 of the armature, a bearing sleeve 28 is disposed on the actuating rod and has its outer surface seated in notch 15. Immediately behind end flange 13, there is provided on the actuating rod a second bearing sleeve 29, held in place by the flattened tip 30 of the rod. Just forwardly of end flange 13, rod 25 is provided with stamped out stop ears 31. Thus, the actuating rod is allowed only a very limited linear travel with respect to the armature. It will be understood from the foregoing that the actuating rod 25 can turn in its mounting, so that tip portion 27 thereof can oscillate about the axis determined by notch 15 and aperture 16.

As will be clear from Figs. 1 and 2, the upwardly projecting extensions 8a on flange 8 are each engaged in a different one of the side notches 17 of armature body portions 12. Extension 22 of bracket 21 projects through the opening in body portion 12 between notches 17, and the enlarged head 23 of such extension is engaged over the top surface of body portion 12 at the sides of semicircular opening portion 19. Such engagement of head 23 with the armature serves to prevent removal against movement in the plane of body portion 12.

In order to bias the combination of the armature 11 l and actuating rod 25 upwardly, atension spring 32 is provided, one end of the spring being fixed to flange 24 of bracket 21 and the other end of the spring being engaged around bearing sleeve 29.

At the front of the device, there is secured to upright flange of plate 3, as by rivets; 33, a plate 34. Being securedto the face of flange 5, plate 34 extends at right angles to the base of the device and thus transversely with respect to tip portion 27 of actuating rod 25. A rocker arm 35 is pivotally mounted adjacent plate 34 to oscillate about an axis at right angles to the plate. Thus, the rocker arm is provided with a dependent car 37 having a bore therethrough, a plain bearing sleeve (not shown) being disposed within the bore. As is usual practice in such constructions, the bearing sleeve. is of a length slightly greater than the thickness of rocker arm 35. A screw 37, the head of which engages a: lock washer 38, extends through such bearing sleeve and is threaded into flange 5.1 A washer 39 carried by screw. 37 between. the rocker: arm and lock washer 38 bears against theend of the. bearing sleeve, clamping the sameagainst plate. 34, leaving the rocker arm free to pivot on the bearing sleeve.

As seen in Figs. 3 and. 4, rocker arm 35' is provided with a pair of downwardly and outwardly slanted slots 40 and to provide cam surfaces 40a and 41:: which: define an inverted V which is disposed so that a line extending through the center of screw 37 and perpendicular to the top edge of the rocker arm bisects the angle between the cam surfaces 40a and 4111. In this connection, it will be observed that the main body of the rocker arm is of rectangular configuration. Thus, when the upper edge of the rocker arm is positioned parallel to base plate 1, a plane perpendicular to base plate 1 and further defined by the axis of that portionof the actuating rod which is parallel to portion 12 of armature 11 passes through the center of screw 37, the center of circular aperture 16 and bisects the angle of the inverted V formed by cam surfaces 40a and 41a.

The rocker arm has an opening above the apex of the inverted V allowing the tip 27 of rod to move unimpeded into contact with cam surfaces 40a, 41a. In addition, it will be noted that rod 25 is of circular crosssection and has a diameter which is smaller than the width of slots 40, 41.

It will be noted that the outer ends of slots 40, 41 are curved to provide a seat for rod 25 to engage after movement along cam surfaces 40a, 41a.

Mounted on side flange 6, as by an angle bracket 42 and screw 43, is a first snap switch assembly 44. Similarly mounted on side flange 7 is a second snap switch assembly 45. The snap switch assemblies are identical and only assembly 44 will be described. From Fig. 1, it will be seen that this switch assembly includes two pairs of vertically spaced fixed contacts 46 and two movable contacts 47 each disposed between a different one of the pairs of fixed contacts. Each movable contact 47 has a bifurcated end, the legs of which engage an abutment 48. Centered between the two pairs of fixed contacts and extending forwardly to rocker arm 35 is a leaf spring 49 carrying a transversely extending insulating plate 50. For each movable contact 47, plate 50 is equipped with a bifurcated member 51 engaging the corresponding abutment 48 in opposition to the movable contact. Corresponding sets of movable contacts 47 and opposing bifurcated members 51 are interconnected by a helical tension spring 52. As will be readily understood by those skilled in the art, when the tip of leaf spring 49 is flexed downwardly a predetermined amount, carrying plate 50 downwardly, springs 52 will throw, with a snap action, the movable contacts into engagement wtih the lower ones of the fixed contacts. Conversely, a predetermined movement of leaf spring 49 upwardly will reverse the operation, throwing, with a snap action, the movable contacts into engagement with their corresponding upper fixed contacts.

As seen in Figs. 3 and 4, the rocker arm 35 is provided at eachend with an elongated slot indicated generally at 53 and extending parallel to the long sides of the rectangle defined by the rocker arm. At its mouth, each slot 53 is provided with semicircular working portions 54 disposed in opposition and projecting inwardly with respect to the sides of the slot. The free tip of each leaf spring 49 extends between the working portions 54 of a different one of the slots 53. Thus, pivotal movement of the rocker arm in either direction is always effective to flex one of the springs 49 downwardly and the other of such springs upwardly, so that the two switch assemblies 44 and 45 will be oppositely actuated by each such movement of the rocker arm.

As best seen in Fig, 5, plate 34 is provided with a window 55 the upper edges of which form combination guide and stop means for the tip 27 of actuating rod 25. As best understood from Figs. 1, 3 and 4, the tip 2? extends first through. the spacein rocker arm 35 atforded by slots 40, 41 and thence through the window 55. Window 55 is generally in the form of an isosceles triangle, with the base thereof parallel to base plate 1 and centered on a line at right angles to base plate 1 and extending through the center of screw 37'. When rocker arm is positioned with the upper edge parallel to base plate 1, the inverted V defined by cam surfaces 4%, 41a is centered with respect to the downwardly and outwardly directed edges of window 55 so that apex of the inverted V is in line with and below the apex of window 55. When the rocker arm is pivoted. to the limit of its travel in either direction, the width of slots 40, 41 are such that the outer edge of the corresponding slot 40, 4t will lie outside window 55.

Assuming coil 9 to be die-energized, so that the armature and actuating rod are urgedtotheir uppermost positions by spring 32, as seen in Pig. 1, tip 27 of the actuating rod is located at the apex of window and so occupies position a, Fig. 5. Assume now that the rocl-acr arm occupies the position of Fig. 3, so that snap switch assembly 44is actuated to bring two movable contacts into engagement with the lower fixed contacts, while the movable contacts of switch assembly 45 are in engagement with the upper fixed contacts of that assembly. Now, upon energization of coil 9, as the armature pivots downwardly toward the core 1 .0, tip 27 is moved down-- wardly to position b, Fig. 5, there being no rotation of actuating rod 25. Because of the disposition of rocker arm 35, when tip 27 of the actuating rod reaches point b, it engages the cam surface 41a. Tip 27 is therefore cammed to the right, as the drawings are viewed, so that actuating rod 25 rotates in aperture 16 and bearing sleeve 28, downward movement continuing until tip 27 reaches the seat at the end of slot 41 and is accordingly located at point c. The spacing of the armature from the core, the spacing of the long leg of rod 25 from the armature and the spacing of tip 27 from the long leg of rod 25 is such that tip 27 reaches point 0 well before the armature has completed its downward pivotal motion toward core 10. Accordingly, rocker arm 35 is pivoted to the position seen in Fig. 4, with tip 27 of the actuating rod finally coming to rest at point d, Fig. 5, asthe armature com.- pletes its travel. Such pivotal motion of the rocker arm actuates switch assemblies 44, 45 to contact positions opposite from those seen in Fig. l, as will be understood by comparison of Fig. 4 with Fig. 3.

Upon de-energization of coil 9, spring 32 returns the armature and actuating rod to their upper positions. that is, to the positions seen in Fig. 1. Friction between rod 25 and the various bearing surfaces tends to hold rod 25 in the angular position attained when at point d. Tip 27 of the actuating rod hence moves quickly up ward and out of engagement with the seat at the end of cam surface 410 to point e, Pig. 5, engaging downwardly and outwardly slanting edge 56 of window 55. supward movement of the armature and actuating rod continues, tip 27 rides along edge 56 and into engagement with downwardly and outwardly slanting window edge 57, disposed at an angle more nearly horizontal than is edge 56. At its opposite side, window 55 is provided with corresponding downwardly and outwardly slanting edge portions 58 and 59. The two uppermost edge portions 57 and 59 of the window join to form the apex of window 55 which is disposed on a line drawn through the center of screw 37 at right angles to the plane of base plate 1. As the upward movement of armature 11 and actuating rod continues, tip 27 reaches the junction point between window edges 57 and 59, and is accordingly stopped in dead center with respect to the axis of oscillation of the rocker arm. Since tip 27 is stopped, it will be understood that the entire assembly comprising the actuating rod and armature is also brought to a stop. If there should be any overtravel of tip 27 onto window edge 59, the tension of spring 32 will be elfective to return tip 27 to dead center. Hence, the actuating rod is now disposed in precisely the correct position for proper operation upon the next energization of coil 9.

Upon such next energization, it will be understood that tip 27 of the actuating rod will travel a path including points a, b, c and d, Fig. 5. Such movement will, of course, pivot rocker arm back to the position seen in Fig. 3 and so return the snap switch assemblies 44, 45 to the condition seen in Fig. 1. Upon de-energization of coil 9, tip 27 now moves upwardly, because of the action of spring 32, into engagement with window edge 58, then travels along such edge onto window edge 59 and is finally brought to a stop precisely at the point between window edge portions 57 and 59. During this last cycle of operation, effective to transfer rocker arm 35 from the position of Fig. 4 to the position of Fig. 3,'

it will be understood that energization of coil 9 causes tip 27 to travel along the cam surface a to the seat at the end of slot 40 since the apex of the inverted V formed by cam surfaces 40a, 41a was, as seen in Fig. 4, disposed to the right of the pivotal axis for the rocker arm at the time energization of the coil occurred. Thus, acting in conjunction with tip 27 of actuating rod 25, cam surfaces 40a, 41a and the seats at the ends of slots 40, 41 serve as throwover means effective to assure that successive energizations of coil 9 cause the rocker arm 35 to be pivoted first in one direction and then in the other.

Use of rod 25, mounted both for bodily movement with armature 11 and for oscillatory movement about the axis of the longerleg of the J formed by the rod, provides a simple, durable and inexpensive means capable of actuating the rocker arm in precisely the same fashion for each cycle of operation. Thus, the device is made dependably repetitive in its operation, without recourse to mechanism requiring preciseness of dimension and adjustment.

It should also be noted that the manner in which J- shaped rod 25 is associated wtih armature 11 assures ease of assembly. To install rod 25, it is only necessary to thread tip 27 and portion 26 through opening 16, then lower bearing sleeve 28 into notch 15, and then attach spring 32. While the snap switch assemblies 44, are of conventional construction, their use in the combination of the present invention eliminates the necessity for employing additional spring means to bias the rocker arm 35 to the limits of its pivotal travel. Thus, when the snap switch assemblies have been actuated by movement of rocker arm 35, springs 52 serve to retain the rocker arm positively in actuated position, so that the apex of the V formed by cam surfaces 40a, 41a will be held to the right or left of the stopped position of actuating rod tip 27, as the case may be, so assuring that the tip 27 will engage and travel along the proper one of cam surfaces 40a, 41a upon the next energization of coil 9.

While this self biasing action serves to properly position rocker arm 35, it is equally necessary to precisely position actuating rod tip 27. The particular configuration of opening or window 55, with edge portions 56, 58 and 57, 59 serving as guides to direct the tip to the stop afforded by the junction of edge portions 57 and 59, provides a simple and effective means for accomplishing this function.

What is claimed is:

1. In an impulse-type switching apparatus, the combination of a base; a pair of bi-directional snap switch assemblies mounted on said base in spaced relation and each having an actuating member extending in the same general direction; a rocker arm mounted on said base for pivotal movement in a plane transverse to said actuating members, each of said actuating members being operatively connected to a different end portion of said rocker arm, whereby the snap switch assemblies are actuated in opposite directions upon occurrence of a predetermined amount of pivotal movement of said rocker arm; electromagnetic means mounted on said base between said switch assemblies and comprising a magnetizable core disposed with its axis extending away from said base; a pivoted magnetic armature operatively associated with said electromagnetic means adjacent the end ofsaid core opposite said base; an actuating member mounted on said armature to pivot therewith, said member having an elongated portion extending along said armature and jourualed thereon to allow said member to turn with respect to said armature during pivoting thereof, said member also including a portion projecting toward said rocker arm and terminating in an actuating tip, said rocker arm being provided with angularly disposed throwover surface means directed toward said actuating tip and disposed to be engaged thereby, said surface means including a first portion arranged to cause said tip to pivot said rocker'arm in one direction as said armature is actuated by a first energization of said electromagnetic means and a second portion arranged to cause said tip to pivot said rocker arm in the other direction as said armature is actuated by the next energization of said electromagnetic means; and resilient means connected to the combination of said armature and actuating member to bias such combination away from said electromagnetic means.

2. An impulse switching apparatus in accordance with claim 1 and wherein said armature comprises a fiat plate having upright' end flanges, said elongated portion of said actuating member being jourualed in said end flanges and extending parallel to said plate on the side thereof opposite said electromagnetic means.

3. An impulse-type switching apparatus in accordance with claim 2 and wherein the one of said end flanges adjacent said rocker arm is provided with a circular opening and the other of said end flanges is provided with a notch, said actuating member consisting of a rod of circular cross section, said rod having the configuration of a J, the longer leg thereof extending through said circular opening and said notch and the shorter leg of the J constituting said actuating tip.

4. An impulse-type switching apparatus in accordance with claim 3 and wherein the longer leg of said actuating member extends beyond said other end flange of the armature, said resilient means being a tension springv having one end connected to said base and the other end connected to said rod adjacent said other end flange of the armature.

5. In a switching apparatus of a type described, the

combination of an electromagnetic power device comwith a seat provided; at the. end of each cam surface away from the apex of the V; an actuating member comprising an elongated portion extending along and spaced from said armature on the side thereof opposite said rocker arm and a second portion extending toward said rocker arm and terminating in an actuating tip; means carried by said armature and mounting saidactuating member, whereby said actuating member pivots with said armature to bring said actuating tip into engagement with one of said cam surfaces upon energization of said power device, said means providing for oscillatory movement of said actuating member about the longitudinal axis of said elongated portion; the pivotal axisof said rocker arm and the oscillatory axis of said actuating member defining a plane which contains said actuating tip when said power device is de-energized and bisects the angle of said V when, said rocker arm is positioned so that the apex of said V lies on said plane; and resilient means connected to the combination of saidarmature and actuating member to bias the same in a direction away from said rocker arm.

6. In a switching apparatus, the combination of frame means; electromagnetic means mounted on said frame means; an armature of magnetic material pivotally mounted on said frame means and operatively disposed with respect to said electromagnetic means; a spring carried by said frame and connected to said armature to bias the same away-from Said electromagnetic means; an actuating rod having a first portion extending along and spaced from said armature on the side thereof opposite said electromagnetic means,- said first portion of the actuating rod being journaled on said armature. whereby said actuating rod pivots with the armature-but is capable of rotary movement'with respect thereto, said actuating rod including asecond portion extending generally in-the direction of said frame means'and terminating in an actuating tip; a rocker arm mountedon said frame means for pivotal motion about an axis at right angles to the pivotal axis of said armature and provided with twocam surfaces which intersect to form a V with the apex of the V directed toward said actuating rod, the other ends of the cam surfaces formed to provide aseat for said actuating tip; the axis of rotation of said actuating rod andvthe pivotal axis of said rocker arm-defining a plane which bisects the angle of said V when said rocker arm is-positioned so that the apex-of-said V lies on said plane; and apair of snap switch devices-mounted on said frame means one at each side'of said electromagnetic means, each of said switch devices including an actuating member extending toward an end portion of said rocker arm and connected therewith for movement by said rocker arm, said snap switch devices being constructed to apply to said rocker arm a resilient biasing force tending to restrain the same against pivotal movement.

7. In an impulse switching device, the combination of electromagnetic power means comprising acoil, a core and a. movable armature arranged adjacent one end of said core; a rocker arm disposed adjacent said power means and mounted for pivotal movement about an axis extending laterally of said core, the armature of said power means extending generally in the direction of said axisand being spaced a substantial distance therefrom so as to move-toward and away from said rocker arm upon energization and de-energization, respectively, of saidpower means; said rocker arm having a pair of cam surfaces which intersect to define a V opening away from said armaturewith a seat provided at each of the other ends of the cam surfaces; an actuating member having a first portion extended parallel to said armature on the-side-thereof opposite said core, and a second portion extending toward said rocker arm and terminating in a tip portion'extending parallel to said first portion; bearingmeansfi'xed to said'armature, said first portion ofsaid' actuating memberbeing journaledin saidbearing means;-

whereby said actuating member shifts with said armature and is capable ofoscillatory movement about the longitudinal axis of saidfirst portion to allow said tip to follow along either of saidcam surfaces until engaged, by the seat atthe end of' the cam surface; resilient means connected to the combination of said armature and actuating memberto bias the same away from said core; a stationary-plate disposed adjacent said rocker arm and extending transversely of the pivotal axis thereof; said plate being provided with an opening through which said tip portion of said actuating member extends, said opening having edge portions defining a stop for said tip portion of said actuating member at a point in line between the pivotal axis of said rocker arm and the oscillatory axis of said actuating member, said edge portions alsoextending from suchstop away from the armature to provide guide surfaces effective to directsaid tip portion,

to such stop when the combinationof 'said'armature and actuating member-ismoved away from said core by said resilient means; and switch means operatively associated with said rocker arm for actuation thereby as the rocker arm is pivoted by said actuating member upon energiza tion of said coil.

8. In an impulse switching device, the combination of an electromagnetic power device comprising a coil, a core, and a pivoted armature-arranged adjacent one end of said core; a rocker arm disposed adjacent said'power device and mounted for pivotal movement about an axis at right angles to the pivotal axis of said armature and extending through said core, said rocker arm having a pair of cam surfaces which intersect to define a'V opening away fromsaid armature with a seat at each of the other ends of the surfaces; an actuating member having a first portion extending parallel to said armatureonthc side thereof opposite said core, and a second portion extending toward'said rocker arm and terminating in a tip portion extending parallel to said first portion; means mounting said actuating member on said armature to pivot therewith, said means allowing oscillatory move ment of said actuating member along the longitudinal axis of said first portion to allow said tip to follow along either of said cam surfaces until engaged in the seat at the end of the surface; resilient means connected to the combination of said armature and actuating member to bias the same away from said core; a combination guide and stop plate fixed adjacent said rocker arm, and ex-- tending transversely of the pivotal axis thereof, said plate being provided with an opening through which said tip portion extends, said opening'having edge portions converging toward said armature and joining to define stop means disposed to locate said tip portion-of said actuating member at a point on a line between the pivotal axis of said rocker arm and the oscillatory axis of said actuating member when said coil is de-energized; and switch means operatively associated with said rocker arnr for actuation thereby as the rocker arm is pivoted by said actuating member upon energization of said coil;

9. In an impulse switching device, the combination of a base; electromagnetic power means mounted on'said base and comprising a coil, a core and an armature mounted adjacent the end of said core for movement toward and away from the same; a stationary plate mounted on said base beside said power means and extending generally parallel to said core, said plate having an opening, edge portions of which converge toward said armature; an actuating member mounted on said armature for movement therewith and also for oscillatory movement about an axis parallel to said armature, said actuating member including a portion projecting from said armature to said plate and terminating in a tip portion extending through said opening; resilient means connected to said base and the combination of said armature and actuatingmember and operativcly-arranged tobias suchcombination away from said core, vz said edge portions of said opening serving to guide the 9 tip of said actuating member to a stop position when the combination of said armature and actuating member is moved' away from said core by said resilient means; a rocker arm disposed adjacent said plate and mounted for pivotal movement about an axis extending through said plate and located on the side of said opening opposite said armature, said rocker arm being provided with a pair of cam surfaces which intersect to define a V opening away from said armature, the other ends of the surfaces each having a seat, said cam surfaces being disposed to guide the tip portion of said actuating member to the seat at the end of the cam surface engaged by said tip portion; the oscillatory axis of said actuating member, the stop defined by said opening, and the pivotal axis of said rocker arm all lying substantially in the same plane, said plane bisecting the angle or" the V when said rocker arm is positioned so that the apex of the V lies on said plane; and switch means operatively associated with said rocker arm for actuation thereby as the rocker arm is pivoted by said actuating member upon energization of said coil.

10. In a switching apparatus of the type described, and in combination, an electromagnet having a pivoted armature, resilient means biasing said armature away from said electromagnet, a rocker arm disposed beside said electromagnet and mounted for pivotal movement about an axis at right angles to the pivotal axis of said armature, an actuating rod comprising an elongated portion extending along and journaled on said armature, and a portion disposed at an angle to said elongated portion, said last mentioned portion extending toward said rocker arm and terminating in an actuating tip projecting therefrom in a direction substantially parallel with said elongated portion, said rocker arm having an opening through which said actuating tip extends, the edges of which opening provide angularly disposed throwover surfaces with which said actuating tip engages, means including said throwover surfaces whereby operation of said armature by successive energizations of said electromagnet cause said actuating tip to swing said rocker arm on its pivot alternately in opposite directions, and switch means operatively associated with said rocker arm for actuation thereby.

11. In a switching apparatus of the type described, and in combination, an electromagnet having a pivoted armature, resilient means biasing said armature away from said electromagnet, a rocker arm disposed beside said electromagnet and mounted for pivotal movement about an axis at right angles to the pivotal axis of said armature, an actuating rod comprising an elongated portion extending along and journaled on said armature, and a portion disposed at an angle to said elongated portion, said last mentioned portion extending toward said rocker arm and terminating in an actuating tip projecting therefrom in a direction substantially parallel with said elongated portion, said rocker arm having a V-shaped slot with closed ends, diverging in a direction away from said armature, with which slot said actuating tip engages, means associated with said rocker arm whereby successive operations of said armature by said electromagnet cause said actutaing tip to travel first along one arm of the V from the apex to the end and then along the other, so as to swing said rocker arm on its pivot alternately in opposite directions, and switch means o-peratively associated with said rocker arm for actuation thereby.

12. In a switching apparatus of the type described, andin combination, an electromagnet having a pivoted armature, resilient means biasing said armature away from said electromagnet, a rocker arm disposed beside said electromagnet and mounted for pivotal movement about an axis at right angles to the pivotal axis of said armature, an actuating member pivotally mounted on said armature to turn about an axis also at right angles to the pivotal axis of said armature, said member having a portion extending from the pivot thereof toward said rocker arm, and terminating in an actuating tip projecting therefrom in a direction substantially parallel with the pivotal axis of said member, said rocker arm having an opening through which said actuating tip extends, the edges of which opening provide angularly disposed throwover surfaces with which said actuating tip engages,

means including said throwovcr surfaces whereby operation of said armature by successive energizations of said electromagnet cause said actuating tip to swing said rocker arm on its pivot alternately in opposite directions, and switch means operatively associated with said rocker arm for actuation thereby.

References Cited in the file of this patent UNITED STATES PATENTS 1,448,033 Nelson Mar. 13, 1923 2,235,104 Greenly Mar. 18, 1941 2,236,318 Lamel et a1 Mar. 25, 1941 2,391,444 Burch Dec. 25, 1945 2,466,292 Wolf Apr. 5, 1949 2,574,399 Lamb Nov. 6, 1951 2,813,949 Klein Nov. 19, 1957 

